Your Microsoft Windows Defender protection tool may report error 0×80070003. This is primarily due to Windows Installer issues, where the updates and patches are not getting installed properly. To resolve this issue, you should follow the steps below:
1. Log in to your computer as an “Administrator”
2. Run Windows Update and install all updates
3. Verify that all the updates are installed properly
4. Download and then install the latest version of Windows Installer (4.5) from the following link:
5. Download the Windows Installer cleanup utility from the link below. This will clean up any entries for failed installations on your computer and will allow troublefree installation of updates and patches.
http://www.softpedia.com/get/Security/Secure-cleaning/Windows-Installer-CleanUp-Utility.shtml
6. Now reinstall Windows Defender and run the Windows update again
